Low tech woman seeks simple answers and solutions for bringing my Mac Air laptop on a plane to Germany and being able to travel to nearby countries and have the power cord and voltage be compatible. I saw something online for an airplane power mag cord which can be used. I saw the World Travel Kit for Apple online, but I'm not sure if this is overkill. What's the minimum requirements I will need?

Yes you can. It works, fine for mine. Since I have both Mac books. I am only using the 85w. You can use a higher watt to charge a lower watt item. Just you cannot use a lower watt for a higher item. Go read a few and they all agreed.

The white box is a built in power converter so you should be fine with plugging it in as long as you have the adapter that changes plug types. You can check to see if other things are converters if it has something like Input: 100-240V~1.5A 50-60Hz. This shows that an electric current of 100-240 Volts can power the converter without problem, which Spain's electricity falls in. If you cannot find this on a product (though most electronics made in about the last 5-10 years automatically convert) or if you feel you would rather side with caution you can but a converter, but only leave it plugged it when you need the power because converters burn out quickly from overheating if you leave them plugged in too long.

All apple power adapters for macbook pro/air are working voltage at 100-240VAC and 50/60Hz. So you can take it everywhere in the world. But the AC power plug/cable may be different in different country. You should notice this.

Yes, it will work, but you need an adapter plug ($9.99 at Radio Shack, Model: PCC-1 | Catalog #: 273-1448). New Zealand electrical grid is 240 V, 50 Hz. Written on the side of the Power Adapter is: "Input 100 - 240 V" and "50 - 60 Hz". That covers it.